数字体层图像后处理方法对检测肺结节准确性的影响

Impact of image processing in digital tomosynthesis on pulmonary nodules detection accuracy

目的探讨数字体层图像两种后处理方法（位移叠加法与滤波反投影法）对肺结节检测准确性的影响。方法采集经CT证实的50例肺部结节患者的数字体层图像,采用滤波反投影法和位移叠加法进行后处理。由3名不同年资的放射诊断医师阅片并记录评分结果。102个CT证实的结节按直径分为3组：〈5 mm、5~10 mm、〉10 mm组;按密度分为实性密度组及毛玻璃密度组。对两种处理方法检出的肺结节进行统计分析。结果位移叠加法检出肺结节52个,滤波反投影法检出86个,差异有统计学意义（P〈0.001）。对于直径〈5 mm和5~10 mm组,滤波反投影法检出的肺结节数均多于位移叠加法（P=0.001、0.005）。结节直径〉10 mm时两种方法的检出数量差异无统计学意义（P=0.317）。在不同密度组中,滤波反投影法检出的结节亦较多,与位移叠加法差异有统计学意义（P均〈0.05）。结论滤波反投影法对检出直径≤10 mm的肺结节、实性结节和毛玻璃结节均优于位移叠加法。

Objective To evaluate the effect of shift-and-add（SAA） and filtered back projection（FBP） in digital tomosynthesis on pulmonary nodules detection accuracy.Methods Fifty patients with small nodules confirmed by chest CT were selected.Digital tomosynthesis images were obtained and processed with SAA and FBP.Three radiologists of different experiences independently reviewed and recorded the results of pulmonary nodules.Totally 102 nodules confirmed with CT were devided into 3 groups： Group of nodules 5 mm,5—10 mm and 10 mm,respectively,and 2 groups according to the density： Group of solid density nodules and ground-glass density.The results of SAA and FBP were analyzed statistically.Results SAA detected 52 pulmonary nodules,while FBP found 86（P0.001）.For nodules with diameter 5 mm and 5—10 mm,FBP displayed more nodules than SAA（P=0.001,0.005）,while no difference was found between two methods for 10 mm group（P=0.317）.For solid density and ground-glass density nodules,FBP showed more nodules than SAA（both P0.05）.Conclusion FBP is superior to SAA in detection of nodules with diameter ≤10 mm,small pulmonary nodules with solid density and ground-glass density.